1. Field of the Invention
The present invention relates to a heat exchanger employed for exchanging heat between two fluids, for example, one fluid, that is a strong acidic or a strong alkaline medical fluid employed in an Integrated Circuit production line (i.e., IC production line) inside a clean room, or various fluid such as a strong corrosive fluid, and another fluid, that is a heat transfer medium such as a cool medium or a heat medium. Moreover, the present invention relates to a method of producing the same.
2. Description of the Prior Art
Conventionally, the above noted heat exchanger having a structure, for example, shown in FIG. 8 is known. In this heat exchanger, a cylindrical shell 83 is fixed in a liquid sealing state, between fixing plates 81 and 82 made of polypropylene, arranged on either side, connectors 84 and 85 made of PTFE (polytetrafluoroethylene) or PFA (perfluoro-alkoxyfluoro Plastics), having a two step-cylindrical shape, in a liquid sealing state, and cylindrical sheath rings 86 fused into the right and left connectors 84 and 85 so that it may be positioned inside the shell 83. A number of fluororesin tubes 87, concretely made of PFA, are gathered for making a bundle, thus forming a tube bundle 88 as a heat transfer pipe. Both ends arranged longitudinally of the tube bundle 88 are fixed to the sheath rings 86 by fusing. Moreover, the connectors 85 and 84 have paths 89 and 90 for medical fluid. The shell 83 is provided with a cooling water inlet 91 and a cooling water outlet 92 for circulating the cooling water as an example of the heat transfer medium (or heat-exchanging-fluids such as a cool medium or a heat medium).
In the heat exchanger, a fluid to be heat-exchanged (or a fluid to be cooled or heated) is circulated inside each fluororesin tube 87 via paths 89 and 90 inside the connectors 84 and 85. Heat exchange is conducted between the fluid to be heat-exchanged and a cooling water circulating outside of the tube bundle 88 via the cooling water inlet 91 and the cooling water outlet 92 of the shell 83.
At both ends in the longitudinal direction of the tube bundle 88, respective resin tubes 87 are contacted with each other, thus being positioned in a honeycomb structure as shown in FIGS. 9 and 10. Gaps inevitably formed between the respective resin tubes 87 disposed in such a honeycomb structure, are closed by fusing the resin tubes 87 with each other. As a result, gaps formed inevitably between the resin tube 87 and sheath ring 86 are closed by fusing them. Therefore, in both ends in the longitudinal direction of the tube bundle 88, the respective resin tubes 87 included by the tube bundle 88, are contacted to be in a congested state (i.e. congestion structure) having no gap.
However, in case that both ends in the longitudinal direction of the tube bundle 88 have a congested structure having no gaps mentioned above, under the influence wherein the cooling water flows through an inside of the shell 83, the respective resin tubes 87 forming a tube bundle 88 swing, thus applying an excess load to each fusing portion of each resin tube 87 to decrease the strength of the fusing portion with the result that there is fear that the strength of the tubes is lacking.
Furthermore, the resin tubes 87 adjacent to each other are contacted with each other and the ends of the resin tubes 87 are integrally fused into each other, thus decreasing heat emission from the sheath ring 86 and the tube bundle 88 (i.e., tube binding portion) adjacent thereto. Accordingly, there is a problem of hindering a whole of the heat exchanger from being miniaturized in view of keeping heat-exchange efficiency.
Especially, in a clean room for producing an IC circuit or others, all machines and equipment used inside the room are required to be miniaturized. However, in the above conventional heat exchanger, it has been difficult to miniaturize it, whereby there has been a problem wherein a requirement of miniaturizing all machines and equipment are hardly satisfied.